Heads won't roll in "The Guillotines," an ineptly executed period actioner in which the decapitating blades are hardly ever unsheathed or shown in all their grisly 3D glory.

Heads won’t roll in “The Guillotines,” an ineptly executed period actioner in which the decapitating blades are hardly ever unsheathed or shown in all their grisly 3D glory. Starting out as a bromance between imperial assassins, this latest effort from Hong Kong helmer-producer Andrew Lau (“Infernal Affairs”) morphs into a heavy-handed allegory on government oppression, but never delivers a cathartic payoff. Producer Peter Ho-sun Chan’s track record helped presell the $18 million blockbuster to major territories, including North America, but the lack of rip-roaring martial arts or even a half-decent storyline will leave genre aficionados feeling short-changed.

Loosely inspired by Ho Meng-hua’s schlocky 1975 actioner “The Flying Guillotine,” the pic was initially conceived by Chan’s We Pictures as a regular 2D project, with Teddy Chen (“Bodyguards and Assassins”) set to direct. But the production was temporarily suspended in April 2011 — reportedly due to script issues, which may explain the stylistic incongruities — and resumed months later with Lau at the helm.

The film takes its name from a squad of assassins assembled by Qing dynasty Emperor Yongzheng to destroy his many enemies, such as the Herders (most of them Han Chinese who resent their Manchu invaders). The Guillotines have been trained by Gong’e (Jimmy Wang) to behead their opponents with a weapon known as xuedizi, as confidently demonstrated in the pic’s strong opening sequence.

Resembling a frisbee with blades, the xuedizi’s manga-like design reps a cool improvement on the model used in the original film and its four spinoffs, and although the 3D images aren’t the sharpest, these weapons do leap dynamically out of the frame, an effect aided by Azrael Chung’s whiplash editing. Alas, these nifty gadgets never see the light of day again as the screenplay strays from its promising genre beginnings.

The Guillotines capture the Herders’ leader, Wolf (Huang Xiaoming, “The Message”), but he manages to escape and even makes off with Gong’e’s daughter, Musen (pop idol Lee Yuchun). Under the wary eyes of Royal Guard captain Haidu (Shawn Yue, “Motorway”), Guillotines head Leng (Ethan Juan) and his five comrades pursue the rebels to their stronghold in Guanwu Town. It transpires, through muddled flashbacks, that Haidu and Leng were handpicked at childhood by Yongzheng to be close aids to his heir, Qianlong (Wen Zhang). Leng’s camaraderie with his squad strains his friendship with Haidu, especially when Qianlong takes the throne and decides to trade his outmoded henchmen for new toys from the West — namely, rifles and cannons.

For more than an hour, an uninvolving war of loyalties plays out, one that suspiciously calls to mind the angst-ridden moles in “Infernal Affairs,” though without that film’s psychological intrigue. There isn’t a single scene highlighting the strength of Leng’s relationships with the other Guillotines, who remain largely faceless, and narrative logic and pacing falter even as a mysterious connection develops among Wolf, Leng and Musen. Sporadic mob violence and military reprisals, shot in a jerky handheld style, are what pass for action in between wordy exchanges, and the 3D technology is never put to particularly vibrant use.

Throughout, the Qing monarchy is none-too-subtly depicted as a corrupt, hierarchical dictatorship prone to ethnic discrimination, censorship and armed suppression of dissidents. Although the final showdown bombastically reinforces the film’s ideology, it also rehashes the spectacle in Peter Chan’s own “The Warlords,” with a distant echo of Roland Joffe’s “The Mission,” to numbing effect.

Perfs from the hot young cast are limp, and veterans like Wang (who starred in a 1976 spinoff, “Master of the Flying Guillotine”) and King Shih-chieh (“The Fourth Portrait”) aren’t given meaty enough roles. Huang has a hard time reconciling his character’s inconsistency as Wolf abuses Musen horrifically one moment, then channels Jesus and Gandhi with “equality for all” peace slogans. Saddled with a one-dimensional role and few opportunities for derring-do, Juan is a pale shadow of the manly Chen Kuan-tai, who originated the role in the 1975 pic.

Lau Sai-wan’s production design conjures the squalor of a dusty border town (shot mostly in Taiyuan, North China), and d.p. Edmund Fung’s sandy color palette lends the protags a soiled, shabby look despite the highly stylized lensing. Other tech credits are serviceable.